If you've ever gave up first possession at football or first dibs on something because you lost at rock paper scissors, here's a way to practice without anything at stake (except your pride).

Up there with coin tosses and dice rolls, the classic game of rock paper scissors has settled many an argument. In theory, rock paper scissors is totally random, but it actually isn't (e.g., this guy). Based on psychology and a ton of data, we can predict the chances of what someone will throw based on what they threw last.

For the record, that screenshot is totally a humblebrag. I quickly went down seven games to three. While the normal setting of this game only uses the data it collects on you, the veteran setting of this game gathers data from all the other people it has played.